Chemical feeder

ABSTRACT

A device for controlled feeding of a water-soluble chemical into a water line having a pressure varying between a minimum and a maximum in the line. Water flows from the water line into an air impervious chemical mixing tank through a first one-way check valve. When the pressure in the line is less than the air pressure in the tank, an air reservoir in the mixing tank forces the mixture of water and chemical back into the water line through a control valve which is set at a restricted flow value with respect to the first check valve. A second one-way check valve located in the water line between the one-way check valve and the control valve prevents the contents of the mixing tank fed through the control valve from backing up toward the first one-way check valve.

BACKGROUND OF THE INVENTION

The present invention relates to a chemical feeder. More specifically,the present invention relates to a chemical feeder which has no movingparts and is useful for the controlled feeding of a water-solublechemical into a water line wherein the pressure varies between a maximumand a minimum.

Chemical treatment of water, including removal of undesirable sulphurodors, is often necessary. To accomplish this treatment, various devicesin the art seek to feed controlled amounts of a water-soluble chemicalinto a water line. Disadvantageously, however, these devices aregenerally complicated, requiring moving parts subject to wear, whichthus must be frequently replaced. There is, therefore, a need in the artfor an uncomplicated device for the controlled feeding of awater-soluble chemical into a water line which does not include partssubject to extreme wear.

SUMMARY OF THE INVENTION

The present invention overcomes the problems and disadvantages of theprior art by providing a device for controlled feeding of awater-soluble chemical into a water line having a pressure varyingbetween a minimum and a maximum in the line comprising an input couplingto the water line; a first check valve means for preventing flow backthrough the input coupling; an output coupling downstream from the inputcoupling; air impervious chemical mixing tank means providing fluidcommunication between the input and output couplings; and means forcreating a pressure differential between the mixing tank means and theoutput coupling. The invention further includes a second check valvelocated in the water line between the input coupling and the outputcoupling for preventing the contents of the mixing tank fed through theoutput coupling from backing up toward the input coupling.

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate various preferred embodiments ofthe invention and, together with the description, serve to explain theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an apparatus for coupling the mixingtank of the chemical feeder of the invention to a water line.

FIG. 2 is a schematic diagram of one embodiment of the mixing tank ofthe present invention.

FIG. 3 is a schematic diagram of a second embodiment of the mixing tankof the present invention.

FIG. 4 is a schematic diagram of another embodiment of the mixing tankof the present invention which is suitable for use without the couplingapparatus.

FIG. 5 is a schematic diagram of still another embodiment of the mixingtank of the present invention which is suitable for use without thecoupling apparatus.

FIG. 6 is a diagrammatic end view of the embodiment of FIG. 5.

FIG. 7 is a schematic diagram of another embodiment of a containersuitable for use in a mixing tank such as shown in FIGS. 2 and 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In private wells, water pressure commonly varies 20 to 30 pounds persquare inch (p.s.i.) between the low pressure point where the well pumpstarts and the high pressure point where the well pump stops. Thepresent invention utilizes this pressure differential to create an airreservoir inside an air impervious mixing tank of a chemical feeder forintroducing controlled amounts of chemical into a water line wheneverthe pressure in the line is less than the air pressure in the mixingtank. Because the pressure differential between the mixing tank and thewater line is utilized for the controlled feeding, no additional feedpump is required for the chemical feeding device of the presentinvention.

Reference will now be made in detail to the presently preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings.

As shown in the diagram of FIG. 1, the device of the invention forcontrolled feeding of a water-soluble chemical into a water lineincludes air impervious chemical mixing tank means providing fluidcommunication between input and output couplings to the water line. Asembodied herein, the mixing tank 28 is coupled to the main water line 30by lines 29, 29a between an input coupling 32 and an output coupling 35downstream from the input coupling. The invention is especially adaptedto control the feeding of a water-soluble chemical from the mixing tankinto a water line having a pressure varying between a minimum pressure,which turns on a pump, (not shown) and a maximum pressure, which turnsthe pump off, as is well-known in the art.

A check valve 34 in the input line 29 prevents backflow of water throughthe line 29 into the main water line 30. To prevent over-concentrationof chemical flowing from the feeder, it is preferred that a second checkvalve 64 be installed in the main water line 30 between the inputcoupling 32 and the output coupling 35 to prevent any backflow ofwater-containing chemical through the main water line and back into theinput coupling 32 during periods when the pump is not operating. Thecheck valves 34, 64 may be any appropriate conventional type of one-wayvalve.

In accordance with the invention, the controlled chemical feederincludes means for creating a pressure differential between the mixingtank means and the output coupling. As embodied herein, the means forcreating a pressure differential between the mixing tank means 28 andthe output coupling 35 includes a valve 50 in the output line 29a forrestricting the flow of fluid through the output line and the outputcoupling into the main water line 30, having a varying water pressure.

Referring to FIGS. 1 and 2, in accordance with the invention, the mixingtank means includes an elongated vertical cylinder 36, and chemicalstorage means 72a and a chemical and water mixing chamber 42 within thecylinder, the fluid communication including passage means 80 through thechemical storage means 72a into the mixing chamber 42. As embodiedherein, the elongated vertical cylinder 36 is divided into sealinglyengageable upper and lower sections 37 and 37a, respectively, which arethreaded together. An O-ring or rubber gasket 37b may be convenientlyused to render the engagement of upper and lower sections 37 and 37aairtight. Preferably, the cylinder 36 is made of polyvinyl chloride.

As embodied herein, the pressure differential creating means alsoinclude an air reservoir 48 in the cylinder 36 which is subject to thevarying pressure in the water line 30 and which acts on the contents ofthe cylinder 36. The air reservoir 48 is primarily in the upper section37. As stated previously, the pressure differential creating means alsoinclude control valve 50 between the cylinder 36 and the output coupling35. The control valve 50 is set at a restricted flow value with respectto the input coupling 32, whereby the air reservoir 48 feeds thecontents of the cylinder 36 containing a mixture of water and chemicalthrough the control valve 50 when the water pressure in the water line30 varies below the air pressure in the reservoir.

In operation, water flows into the cylinder 36 through the inputcoupling 32, check valve 34 and inlet water line 29 until the airpressure in the reservoir 48 equals the water pressure in the line 30.After solubilizing the chemical in the container 72a and mixing in thechemical and water mixing chamber 42, the water leaves the cylinder 36through output coupling 35 and control valve 50. A filter, not shown,may be employed in the lower section 37a of the cylinder 36 to keepfloating solid material from entering control valve 50.

Because only a small amount of chemically treated water is required tobe introduced into the main water line 30, control valve 50 is set at arestricted flow value with respect to the input coupling 32. As water isused from the water line 30, the pressure in the line drops. The airpressure inside the cylinder 36, however, remains higher because of therestricted flow value of the control valve 50. The resulting pressuredifferential forces the water through the control valve 50 into the line30. At times, the air pressure in the reservoir 48 and the waterpressure in the water line 30 are equal and the chemical feeder stops.As soon, however, as a water tap is opened, the water line pressuredrops and the chemical resumes feeding.

It may be desirable to install a holding tank, not shown, in the waterline 30 after the output coupling 35 to average out the concentration ofchemical in the water and offset any variation of chemical feed into thewater caused by varying pressures and varying rates of flow. Moreover,in the case of feeding chlorine, a charcoal filter, not shown, may beemployed downstream from the output coupling 35 to remove any excesschlorine.

The embodiment of the chemical feed control device of FIG. 2 utilizes asomewhat simplified version of the mixing tank. As embodied in FIG. 2,the water input from coupling 32 flows directly into the chemical andwater mixing chamber 42 of mixing tank 28. An elongated verticalcontainer 72a, where the chemical is located, extends from near thebottom of the lower section 37a into the upper section 37. A tube 80,substantially concentric with the container 72a, extends from near thebottom portion of the container to an aperture 76 in the container, therim of the tube being sealed to the edge of the aperture. If desired, afilter 82 may be inserted between the bottom of the tube 80 and thebottom 81 of the container 72a.

As the water levels vary in the chemical and water mixing chamber 42 andin the elongated vertical container 72a, both the inlet and outlet ofwater into and from the elongated vertical container 72a pass throughthe bottom of the elongated vertical container 72a, thus ensuring aconstant mixture of chemical. When the water level in the chemical andmixing chamber 42 is rising, water enters the container 72a through theaperture 76, passes through the tube 80 and filter 82, and mixes withthe solid chemical. When the water level in the container 72a andchemical and water mixing chamber 42 is falling, the water, containingdissolved chemical, passes back out through filter 82, tube 80 andaperture 76 into chemical and water mixing chamber 42 and out ofcylinder 36 through output coupling 35 and control valve 50.

The embodiment shown in FIG. 3 is similar to the embodiment of FIG. 2 inmany respects and like elements bear the same reference numerals. In theembodiment of FIG. 3, the mixing tank 28 includes an elongated verticalcylinder 36 which is divided into sealingly engageable upper and lowersections 37 and 37a, respectively.

In accordance with the invention, the mixing tank 28 includes means fordirecting a portion of the water flowing through the input coupling 32to a second control valve 68. As embodied herein, the latter meansincludes water bypass 69.

The mixing tank 28 also includes, in accordance with the invention,means for directing a second portion of the water flowing through theinput coupling 32 into the chemical and water mixing chamber 42. Asembodied herein, the latter means include secondary water inlet 70.

As embodied in mixing tank 28, the chemical storage means includes anelongated vertical container 72a located within the chemical and watermixing chamber 42. A solid, water-soluble chemical useful for watertreatment is contained within container 72a. Preferably, container 72ais a cylinder and the top 73 of the container 72a is above the highwater level within cylinder 36.

A water injection tube 74 is in fluid communication with the secondcontrol valve 68 and extends to the inside bottom portion 75 ofcontainer 72a. Thus, the portion of water allowed to flow through waterinjection tube 74 by second control valve 68 mixes with the solidchemical at the bottom portion 75 of the container 72a. Since the amountof water which flows through container 72a is controlled by secondcontrol valve 68, the concentration of the liquid chemical inside thecylinder 36 is increased by opening second control valve 68 anddecreased by closing second control valve 68.

The container 72a also contains an aperture 76 for discharge of watercontaining the dissolved chemical. Preferably, the aperture is alwaysbelow the varying levels of water in the cylinder 36 under the varyingwater pressures.

The liquid level inside elongated vertical container 72a and the liquidlevel inside elongated vertical cylinder 36 are at substantially thesame height, except when water is entering the cylinder 36 and thecontainer 72a. As the water level in both the cylinder 36 and thecontainer 72a drops, however, water containing dissolved chemical flowsthrough the aperture 76 and mixes with the raw water in the chemical andwater mixing chamber 42 and then flows out of the cylinder 36 throughthe output coupling 35 and the first control valve 50.

Use of container 72a, second control valve 68 and water injection tube74 advantageously reduces the amount of undissolved solid chemical inthe chemical storage chamber 72a, promotes mixing of the chemical withthe water, and also allows for better control of the degree ofconcentration of the chemical.

It has been found that when HTH chlorine is used as a solid chemical inthe embodiment of the invention featured in FIG. 3, the concentration ofchemicals inside the cylinder 36 remains more constant if the aperture76 of the elongated vertical container 72a is below the lower waterlevel at all times. However, aperture 76 may be located above the lowerwater level in order to limit the concentration of chemical insidecylinder 36.

The embodiment shown in FIG. 4 is similar to the embodiment of FIG. 2 inmany respects, and like elements bear the same reference numerals. Inthe embodiment of FIG. 4, the chemical storage means includes a basket40 in which a solid water-soluble chemical is placed. The elongatedvertical cylinder 36 also includes a chemical and water mixing chamber42.

In the embodiment of FIG. 4, fluid communication through mixing tank 28includes water inlet line 38, water feed cup 43 and an aperture 44 inthe water cup which allows drainage of the cup when water is notflowing. This eliminates a saturated mixture. When fluid is moving intocup 43, it will mix with the chemical in basket 40 and overflow cup 43into water mixing chamber 42.

The water inlet line 38 is coupled to line 29 through an aperture 39 inthe lower section 37a of the cylinder 36, the line 38 being sealed intothe aperture. The water line 38 extends upwardly through the mixingchamber 42 into the water cup 43, which is positioned in the uppersection 37 of the cylinder 36.

The basket 40 is adjustably positionable within the feed water cup 43.In accordance with the invention, the cylinder 36 contains means forlocating the basket 40 at different levels within the water cup 43. Asembodied herein, the means for locating the basket 40 at differentlevels are the adjusters 45, such as studs fixed to the inner surface ofthe section 37.

Accordingly, if it is desired to dissolve greater amounts of chemicalinto the water, the basket 40 can be positioned on the adjusters 45 sothat all or at least a portion of the basket is below the level of waterin cup 43. The varying levels of water in cylinder 36 should always bebelow chemical feed cup 43 to allow proper drainage of the feed cup.Similarly, if it is desired to dissolve smaller amounts of chemical inthe water, the basket 40 can be positioned on the adjusters 45 so thatthe entire basket 40 is inside feed cup 43.

In this embodiment, both the basket 40 and the mixing chamber 42 aresubject to the pressure of air reservoir 48.

Solid chemicals useful for treating water, such as HTH chlorine (Calciumhypochlorite) and trichloro-s-triazinetrione, can be used in allembodiments of the invention, although the latter will work best in theembodiment shown in FIG. 4, i.e. in basket 40, and the former works bestin the embodiments shown in FIGS. 2, 3, 5 and 7. Further, liquidchemicals may be utilized in the embodiments of FIGS. 2, 3 and 5.Because the upper and lower sections 37 and 37a, respectively, of thecylinder 36 are sealingly engageable, the unit can be separated forreloading the chemical.

While reloading the chemical, the water must be shut off at the source,and a drain 52 opened to drain and clean out the cylinder 36. The uppersection 37 is then removed, the basket 40 is filled with solid chemicaland positioned again on the studs 45, and the upper section 37 isreplaced. After the drain 52 is closed, the water may be turned back onat its source.

The embodiment of the mixing tank 28 shown in FIGS. 5 and 6 can bemechanically connected to water line 30 in the manner shown in FIG. 1 toform yet another embodiment of the invention. Although the mixing tank28 is similar in some respects to the mixing tank shown in the otherfigures, in this embodiment the lower section 37a is not cylindrical,and the major portion of the container 72a is in the upper section 37.

When the embodiments shown in FIGS. 4 or 5 are being used without thecoupling device of FIG. 1, it may be necessary, if a hose outlet is usedupstream from line 29 and over-chlorination is occurring, to include acheck valve in the water line 29 upstream from the input coupling line29.

FIG. 7 illustrates an alternate embodiment of a container 90 suitablefor use in a mixing tank 28 as shown in FIGS. 2 and 5. Container 90,shown in FIG. 7, may be used in lieu of container 72a, shown in FIGS. 2and 5.

Container 90 comprises an elongated vertical tube of substantiallycircular cross section which is open at its upper end 91. Tube 92 issituated within, and substantially concentric with, container 90. Tube92 extends substantially the entire length of container 90 and is openat its upper end 93. Solid chemical such as HTH chlorine is packedinside tube 92. Water enters container 90 via port 94 in the containerwall when the water level in mixing chamber 42 exceeds the level atwhich port 94 is located. Thus, as in the embodiments shown in FIGS. 2and 5, the liquid chemical concentration may be increased by situatingport 94 at a lower level on the wall of container 90, and vice versa.Water from container 90 enters tube 92 via ports 95 located in the lowertube wall, and mixes with the solid chemical contained therein. Toprevent clogging, it is preferable to construct tube 92 with a pluralityof ports 95 at its lower end. Further, for ease in handling tube 92, andin order to make tube 92 insertable in container 90 in either direction,it is preferable to construct tube 92 with a plurality of ports 95 atboth ends.

Except for the differences noted above, the functioning of container 90in the chemical mixing tank of the present invention is similar to thefunctioning of container 72a, as shown and discussed in connection withFIGS. 2 and 5.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the embodiments of thepresent invention without departing from the scope or spirit of theinvention. Thus, it is intended that the present invention cover themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

We claim:
 1. A device for controlled, pressure-actuated feeding of awater-soluble chemical into a water line having a pressure varyingbetween a minimum and a maximum in the line, comprising:an inputcoupling to the water line; a first check valve for preventing flow backthrough said input coupling; an output coupling to the water linedownstream from said input coupling; fluid-tight chemical mixing tankmeans in fluid communication between said input and output couplings forpermitting mixing of the chemical and the water therein, said mixingtank means including an elongated vertical cylinder divided intosealingly engageable upper and lower sections, chemical storage means,and a chemical and water mixing chamber, said storage means and saidmixing chamber being situated within the cylinder, said fluidcommunication including fluid passage means through at least a portionof said chemical storage means and into said mixing chamber; and meansfor creating a pressure differential between said mixing tank means andsaid output coupling as a result of a decrease in the water pressure inthe line below the maximum, thereby forcing chemical and water from saidtank means into the line via said output coupling, said pressuredifferential creating means including an air reservoir situated in saidmixing tank means and a control valve between said tank means and saidoutput coupling, said control valve being set at a restricted flow valuewith respect to said input coupling, whereby the contents of said tankmeans are fed through said control valve by the pressure in said airreservoir acting on said contents when the water pressure in the waterline decreases below the pressure in said air reservoir, both saidchemical storage means and said mixing chamber being subject to thepressures of said air reservoir, wherein said air reservoir is primarilyin said upper section; and wherein said chemical storage means is anelongated vertical container extending from near the bottom of themixing chamber upward through the lower section and into the uppersection of the cylinder, said container having an aperture in the wallthereof lying within said lower section and adapted to be within thefluid of said chemical and water mixing chamber during a portion of eachfilling cycle of said chamber and a tube having its rim at one endsealed to the perimeter of said aperture and the other end of said tubeextending close to the bottom of said container.
 2. The device of claim1 also including a filter inserted between the other end of said tubeand the bottom of said container.
 3. The device of claim 2, wherein whenthe water level in said mixing tank means is rising, water enters saidcontainer through said aperture, tube, and filter, and mixes with saidchemical and wherein water containing dissolved chemical passes back outthrough said filter, tube and aperture into said cylinder, when thewater level in said mixing tank means is falling, said water levelrising and falling as the pressure in said water line varies.
 4. Thedevice of claim 1, further including a second check valve located insaid water line between said input coupling and said output coupling forpreventing the contents of said mixing tank fed through said outputcoupling from backing up toward said input coupling.
 5. A device forcontrolled, pressure-actuated feeding of a water-soluble chemical into awater line having a pressure varying between a minimum and a maximum inthe line, comprising:an input coupling to the water line for receivingthe entire flow thereof; a first check valve for preventing flow backthrough said input coupling; fluid-tight chemical mixing tank means influid communication between said input coupling and the water line forpermitting mixing of the chemical and the water therein, said mixingtank means including (a) sealingly engageable upper and lower sections,said upper section comprising an elongated vertical cylinder, (b)chemical storage means, and (c) a chemical and water mixing chamber,said storage means and said mixing chamber being situated partiallywithin said cylinder and said fluid communication including fluidpassage through at least a portion of said chemical storage means andinto said mixing chamber; and means for creating a pressure differentialbetween said mixing tank means and said water line as a result of adecrease in the water pressure in the water line below the maximum,thereby forcing chemical and water from said mixing tank means into thewater line, said pressure differential creating means including an airreservoir situated in said upper section of said mixing tank means,whereby the contents of said tank means are fed to the water line by thepressure in said air reservoir acting on said contents when the waterpressure in the water line decreases below the pressure in said airreservoir, both said chemical storage means and said mixing chamberbeing subject to the pressure of said air reservoir, said chemicalstorage means comprising an elongated vertical container extending fromnear the bottom of said mixing chamber upward through said lower sectionand into said upper section of said mixing tank means, said containerhaving an aperture in the wall thereof lying within said upper sectionand adapted to be within the fluid of said chemical and water mixingchamber during a portion of each filling cycle of said chamber and atube having its rim at one end sealed to the perimeter of said apertureand the other end of said tube extending close to the bottom of saidcontainer.